If the Internet was the information superhighway, 5G is a future where every street is a highway: no speed limits, no data bottl

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问题     If the Internet was the information superhighway, 5G is a future where every street is a highway: no speed limits, no data bottlenecks. It’s a future perhaps as game-changing as the Internet itself.
    What is 5G? It’s the fifth generation of cellphone service, using three different portions of the spectrum to create a superfast and much more reliable service even if you’re sitting in a basement or stuck in an underground tunnel during rush hour. It’s this reliability of communications—wherever you are—that could lead to innovative products and services.
    Downloads will be more than 10 times as fast as a good 4G connection, meaning you could download a full movie to your phone in seconds rather than minutes. Also, wireless companies could begin competing with cable firms to offer home Internet and TV service.
    Your city’s traffic grid would communicate with cars and vice versa to reduce bottlenecks and improve safety. Smart homes would become smarter and easier to set up. Since 5G would virtually eliminate any delays in streaming video, workers could operate machines remotely and shoppers at home could "try on" clothes by watching a 3D image of themselves dressed in the duds. Futurists call this "the Internet of things," where everything can communicate with everything else.
    Estimates suggest carriers in the U. S. will offer 5G as a premium service at first. Verizon, for example, plans to charge $10 a month extra for the service. Its 5G phones range from $1,000 to $1,300. The rewards to companies could be amazing, with one forecast predicting a $277 billion global market by 2025.
    To achieve higher speeds, 5G uses radio waves in a new area of the spectrum. These radio waves don’t do a good job penetrating walls and buildings, so 5G carriers will have to build a much denser network of small transmitters to complement today’s cell-tower technology. Some critics have raised concerns that exposure to so many radio waves could have health effects. The industry says no studies have uncovered any problems.
    Other experts raise concerns that China-based Huawei, one of the most advanced, and cheapest manufacturers of many 5G network components, will use its equipment to give the Chinese government a secret back door to the data. The Trump administration banned U. S. companies from selling equipment to Huawei, but is now considering exempting some companies from that ban. Britain shows little concern, since its carriers building 5G networks are reportedly using Huawei parts. India, by contrast, has kept away from using Huawei components, even after the company offered assurances there would be no back door.
5G carriers will have to build a much denser network of small transmitters because________.

选项 A、the more the transmitters, the higher the speed
B、5G users will be much more
C、the health effects caused by radio waves can be reduced
D、the radio waves 5G uses are not good at passing through obstacles

答案D

解析 细节题。根据题干中的build a much denser network of small transmitters可定位至第六段第二句These radio waves don’t do a good job penetrating walls and buildings, so 5G carriers will have to build a much denser network of small transmitters to complement today’s cell-tower technology. 本句话前后为因果关系,由so连接。故锁定本题答案句为前半句These radio waves don’t do a good job penetrating walls and buildings “这些无线电波不能很好地穿透墙壁和建筑物”,与D项表达一致,故D项正确。原文并没有阐述发射器数量与速度之间的关系,故A项为无中生有,故排除;B项也属于无中生有,亦排除;C项脱离定位,并且与第六段最后一句The industry says no studies have uncovered any problems“业内人士称没有研究发现任何问题”相悖,故排除。故本题答案为D项。
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